How to Apply for an ITIN With Form W-7 (Step by Step)

An Individual Taxpayer Identification Number (ITIN) is a tax ID the IRS issues to people who need to file or be listed on a U.S. tax return but cannot get a Social Security number. You apply for one with Form W-7. This guide walks through who needs an ITIN, what to send and how to avoid the most common delays.

What an ITIN is (and isn't)

An ITIN is a nine-digit number that starts with 9, formatted like a Social Security number (9XX-XX-XXXX). It is used only for federal tax purposes. It does not give the right to work in the United States, does not make someone eligible for Social Security benefits, and does not change immigration status.

Who needs an ITIN

You may need an ITIN if you are not eligible for a Social Security number and you are:

• a nonresident alien who must file a U.S. tax return, or who is claiming a tax treaty benefit;
• a U.S. resident alien for tax purposes, based on the days you were present in the United States, who must file a return;
• the spouse or dependent of a U.S. citizen or resident alien, listed on their return;
• a nonresident alien student, professor or researcher filing a return or claiming an exception;
• the spouse or dependent of a nonresident alien holding a U.S. visa.

These match the reasons a to h at the top of Form W-7. You tick the one that applies.

Documents you need

The IRS needs proof of identity and foreign status:

• A valid passport is the only document that proves both on its own.
• Without a passport, you send at least two documents from the IRS list, such as a national identity card, a U.S. or foreign driver's license, a birth certificate or a visa. At least one must have a photo, unless an exception applies.

Documents must be originals or copies certified by the agency that issued them. Ordinary photocopies, even notarized ones, are not accepted.

Three ways to apply

1. By mail: send Form W-7, your federal tax return and your documents to the IRS ITIN Operation in Austin, Texas. Your original documents are mailed back, which can take several weeks.
2. Through a Certifying Acceptance Agent (CAA): an IRS-authorized agent can verify most original documents for you, so you don't have to mail them.
3. In person at an IRS Taxpayer Assistance Center: some offices can verify documents by appointment.

In most cases, Form W-7 must be attached to a federal tax return. A few exceptions, such as certain treaty benefits or third-party reporting, let you apply without one; the W-7 instructions explain them.

How long it takes

The IRS usually aims to issue an ITIN in about seven weeks. It can take longer during tax season (January to April) or if you apply from outside the United States. Missing signatures, the wrong documents and plain photocopies are the most common causes of delay.

ITINs expire

An ITIN expires if it is not used on a federal tax return for three consecutive years. If yours has expired and you need to file, you renew it with the same Form W-7, ticking the renew option and including your previous ITIN.

Fill in Form W-7 before you apply

Our free Form W-7 generator walks through every line, from the reason you are applying to your identification documents and previous ITIN, and shows a live preview. Download it to check your answers, then complete and sign the official IRS form. If you also need other forms, see our free W-9 and W-4 generators.

This article is general information, not tax or legal advice. Rules change, so always check the current IRS instructions for Form W-7 or speak with a Certifying Acceptance Agent or tax professional.